On the second page where you calculate total price with taxes, you get numbers that are too high.
329 + 329 × .075 should yield 353.68. Your answer was 531.74, which is much greater.
A simpler, less error-prone way to calculate the total with taxes is
329 × 1.075.
You can do the same with the second part, the no package deal. 512.29 × 1.075 = 550.71, not 875.09